Apparatus and method for the dynamic testing or ordnance

ABSTRACT

A thrust unit is placed in contact with the nozzle of an artillery piece and a power unit applies dynamic force to the thrust unit and thus to the artillery piece to simulate firing of the artillery piece, the power unit has a piston which compresses nitrogen in a closed chamber, and a control unit holds the piston in place with the nitrogen compressed. The control unit is adapted to release the piston and allow the same to displace under the pressure of the nitrogen, the piston being coupled to the thrust unit.

United States Patent Inventor Appl. No.

Filed Patented Assignee Priority APPARATUS AND METHOD FOR THE DYNAMIC References Cited UNITED STATES PATENTS Primary Ekaminer-S. Clement Swisher Anorneywaters, Roditi, Schwartz & Nissen ABSTRACT: A thrust unit is placed in contact with the nozzle of an artillery piece and a power unit applies dynamic force to the thrust unit and thus to the artillery piece to simulate firing TESTING 0R ORDNANCE 5 Claims, 6 Drawing Figs. of the artillery piece, the powerunit has a piston which com- Cl 73/167 presses nitrogen in a closed chamber, and a control unit holds U.S. the piston in place wih the nitrogen compressed. The control Cl Golm 7/00 unit is adapted to release the piston and allow the same to dis- Field of Search 711/432 R, place under the pressure of nitrogen the piston being com 92/134 91/408 pled [0 the thrust unit.

C a. 1 P I 1 H 2 Z 0 /4 e QL I f 2 D A A m APPARATUS AND METHOD FOR THE DYNAMIC TESTING OR ORDNANCE BRIEF SUMMARY THE INVENTION The present invention is directed to methods and apparatus for the testing of the mechanical parts of heavy ordnance or artillery pieces.

The apparatus according to the invention is capable of imparting mechanical recoil and retum-to-firing-position stresses to any heavy ordnance unit or part, such stresses closely approximating those imposed when a projectile is fired.

This apparatus can be used whenever it is desired to subject heavy ordnance, machines, fittings or the like to considerable accelerative forces.

Currently a means for testing elastic links, breech mechanisms or other ordnance elements duringrecoil and return-to-firing-position comprise:

a. torsion, tensile, bending and compression systems capable only of slow speeds considerably distinguishable from the effective velocities developed during actual firing; and

b. actual firing which is burdensome and expends considerable time.

Current dynamic testers (tensiometers, torsimeters, etc., as mentioned above) do not allow representative testing of the ordnance operation and actual firing is impractical and can only be carried out on a very limited scale.

An object of the present invention is to overcome these drawbacks and to provide ,a method and apparatus for imparting controllable forces to the ordnance piece simulating actual firing.

The ordnance piece is anchored to a site by a structure accommodating the anchoring unit of the piece, the anchoring unit being a cradle, saddle or rack, platform, gun carriage or other anchoring unit.

The apparatus according to this invention can apply to the gun muzzle a force parallel to and along the tube axis, adjustable in intensity and duration in such manner that after it is applied, the recoiling mass is impelled at a recoil velocity equal to that which would have been imparted by the powder gas pressure during the firing of an actual projectile. When maximum recoil velocity is reached, the recoiling mass is released from the apparatus of this invention, and then under conditions identical with those of actual firing executes its motion of recoil and return to firing position.

The operation principle of the apparatus is the use of a power source which is based on the expansion and compression of a volume of nitrogen. Y

The nitrogen expansion is governed by a hydraulic arrangement constituting a stop system;

The stress is transmitted to the gun tube by a mechanical thrust system which performs the functions of transmission of stress and release of the tube when the required velocity has been attained. The thrust system then is decoupled to allow the ordnance piece to make a complete return to the firing position.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a longitudinal sectional view through the power unit of the apparatus of the invention;

FIG. 2 is a cross-sectional view through the control unit of l the apparatus of the invention;

FIG. 3 is a section taken along line 3-3 in FIG. 2; FIG. 4 is a sectional view through the thrust unit of the apparatus of the invention as taken along line 4-4 in FIG. 5;

DETAILED DESCRIPTION The apparatus according to the invention is basically constituted by three units: a. a power unit 1 as shown in FIG. 1; b. a control unit 2 as shown in FIG. 2; and

c. a mechanical thrust unit 3 as shown in FIG. 4.

Briefly, the power unit '1 is adapted for storing energy and releasing the energy to thrust unit 3 under the operation of control unit 2. The thrust unit applies energy to the muzzle of the ordnance piece to simulate actual firing of the piece and the thrust unit is releasedfrom the muzzle when maximum recoil velocity is reached whereupon the muzzle continues in recoil and then returns to its initial position in preparation for firing. v

The ordnance piece thereby is subjected to substantially the same conditions as if it were actually fired.

POWER UNIT The power unit is essentially a compression-expansion system, and it comprises a cylinder I0 containing a slidable piston P therein. The cylinder I0 defines a chamber A on one side of piston P for nitrogen gas, and a chamber H on the other side of piston P for a control fluid which is'pressurized by a pump (not shown) and fed to chamber H via feed conduit ll. When the control fluid is pressurized, the nitrogen in chamber A is also pressurized. At this time, the control unit 2 blocks the outlet conduit Ca of the power unit as will be explained later. A needle valve l2 is closed.

When the required pressure has been developed in chamber H, valve 12 is opened and the nitrogen in chamber begins to expand and slowly move the piston P to the right causing a rod 13 to act on thrust unit 3 and engage the same with the muzzle of the ordnance piece as will be explained more fully later. The muzzle is slowly retracted and after a small travel of the order of 2 mm., a switch connected to the ordnance piece is closed whereupon an electropneumatic control device is activated to unlock the control unit 2.

CONTROL UNIT The control unit 2 is in communication with the power unit I via conduit Ca containing the pressurized control fluid. The control unit has a discharge conduit Cd and a piston PI is slidably mounted within the feedpipe Ca to control the outflow of the high-pressure fluid to the discharge conduit Cd. The piston P1 in the position shown in FIG. 2 seals the discharge conduit and in this respect the piston is either carefully machined and placed within the feedpipe with close tolerances or sealing piston rings (not shown) may be employed.

A series of links BI, B2 and B3 is connected to the piston P1 to hold the same in an unstable closed position as shown in FIG. 2.

A safety lock V1 acts on links B3 to hold the linkage in its locked condition and the safety lock is retracted by the electropneumatic control device when the muzzle has been retracted by the prescribed amount and the switch is closed.

A release pawl V2 acts on link B3 to position the linkage and aid in its locking and the pawl V2 is also controlled by the electropneumatic control device.

The link B3 is connected to a resistance means constituted by hollow piston P2 which is displaceable against an air cushion in a chamber AI. said resistance means being connected to link B3 through dashpot arrangement A2. The dashpot arrangement includes a slidable member P3 which is acted on by a spring SI and which acts on fluid contained in a chamber A3 within the hollow piston P2 to wiredraw liquid through a gauged orifice Ml. v

An orifice M2 is optionally provided in the end wall of the cylinder containing piston P2 for the purpose of regulating automatic operation of the control unit to close conduit Ca depending on whether orifice M2 is open or closed.

The arrangement of links B1, B2 and B3 forms a toggle linkage wherein links BI and B2 are inclined at a relatively small angle 6 in the unstable locked position shown in FIG. 2. This angle is of the order of several degrees, and as a consequence, the force which is transmitted from piston P1 to the resistance means will be substantially diminished. Moreover, the toggle linkage is especially adapted to permitrapi'd piston movement at high pressure and to convert this to slower movement at much lower pressures on the resistance means.

ln operation, when pressureis developed in the conduit Ca force is applied to the piston P1 which is held in the position shown in FIG. 2 by the lock V1 and pawl V2. The control unit is operated by retracting lock V1 and pawl V2 for lower working pressures and by withdrawing only lock V1 for higher working pressures. Under the effect of the pressure in conduit 7 Ca piston P1 rapidly displaces upwards in conduit Ca quickly exposing the orifices leading to conduit Cd whereby the power unit 1 is unblocked. During this movement of the piston P1, the toggle linkage collapses slightly and the resistance means. undergoes stress. The dashpot means receives the load from the linkage via link B3 and the piston P2 travels to the left in FIG. 2 to compress the air contained in chamber A1 which effectively brakes the displacement of piston P1. The impact of the resistance unit is substantially diminished by wiredraw of the fluid contained in chamber A3 through the gauged orifice M1 of the dashpot.

The valve is kept open by the pressure present in conduit Ca throughout the flow and it is automatically closed or not depending on whether gauged orifice M2 was previously open or not.

When the control unit has been activated and the power unit released, the nitrogen in chamber A expands transmitting propulsion to the muzzle of the ordnance piece. After an acceleration period, piston P first blocks orifices then the braking orifices 14 of triangular section. The end of the movement of piston P is throttled by oil wiredraw between pad Ta and bush D. I

At the end of the braking period of piston P the recoiling mass of the ordnance piece is driven substantially at its maximum recoil velocity and is released from the thrust system 3 and continues its recoil motion.

' ll-IRUST UNIT The thrust unit comprisesa rotatable thrust block B provided with interior claw couplers Cl and a spring R1. A pneumatic system R is coupled with block B for rotating the same. A rod T1 is mounted within block B and is provided with external claw couplers C2. The rod T1 is coupled to rod 13 of the power unit. The spring R1 is secured to the end of rod T1 and bears against the rear surface of claw couplers C1 of block B. A guide member G on block B guides the movement thereof.

Before expansion of the nitrogen gas in chamber A of the power unit, the claw couplers Cl and C2 are axially aligned in face-to-face relation and transmit the axial force from rod T1 to the block B.

During expansion, the block B transmits the axial force to the muzzle 30 of the gun, and a valve V3 is controlled by a ramp on block B to open communication of pneumatic system R with the ambient atmosphere whereupon spring 31 in system R expands and block B is urged in rotation.

After the braking operation has begun in power unit 1, the claws Cl and C2 are axially engaged and traveling to the right in FIG. 4. Guide G travels to a position in which block 8 is permitted to rotate whereupon the block B rotates under the action of system R and the claw couplers are disengaged. After rotation, block B returns to initial position with rod Tl due to the expansion of spring R1. Block B is therefore released from muzzle 30 and withdrawn therefrom to allow the ordnance piece to undergo a full' return to its firing position.

When a fresh compression of the nitrogen in chamber A is effected, rod T1 is retracted into block B so that claw couplers C2 are to the left of couplers C1 while spring R1 is being compressed, and at the end of the stroke of rod Tl valve V3 causes reverse rotation of block B which placesclaw couplers C1 and C2 again in axial alignment in preparation for release of the power unit 1 by control unit 2.

By way of nonrestrictive example, the following dimensions are. provided for an-apparatus of 40,000 H.P.

Power unit Diameter of piston P 300 mm. Maximum pressure in chamber A 500 kgJcm. Expansion stroke A 80 mm. Braking stroke i 80 mm. Sectional area of orifices 0 and I4 cm. Diameter of pad Ta I05 mm.

Control unit Maximum working pressure 500 kgJcm. Diameter of piston PI mm. Diameter of piston P2 I00 mm. Diameter of bore MI 3 mm. Opening time 0.002 sec. Discharge for pressure of 300 kgvlcm. 5.000 liters/sec. Angle E 2 Maximum shearing stress IO N Initial air pressure in chamber Al 3 to 5 kgi/cmf Thrust unit Air pressure in pneumatic system R 5 kgJcm. Diameter of rod Tl 60 mm. Number of clutchclaws 6 The overall unit has the following dimensions: Horsepower 40.000 CV Maximum working pressure 500 lag/cm. Maximum stroke-end velocity 20 mJsec. Maximum velocity for a 4-ton (metric) recoil-mass fieldpiece l0 mJsec. Mean acceleration I00 g.

Duration of thrust or firing movement I 0.005 to 0.02 see.

What is claimed is: v I

1. Apparatus for the testing of ordnance pieces comprising a power unit adapted for generating thrust for application to an ordnance piece, and thrust unit coupled to said power unit for transmitting thrust to said ordnance piece at the muzzle thereof, said power unit comprising a cylinder, a piston in said cylinder defining on one side thereof, a closed chamber with a gas therein, means acting on said piston on the other side thereof to compress the gas in said closed chamber and hold the same under pressure and to release the piston for rapid movement and means coupling the piston and thrust unit to transmit the rapid movement of the piston to the thrust unit and thence to the ordnance piece, a control unit regulating release of the piston, said means acting on the other side of the piston to compress the gas comprising means for the supply of a liquid under pressure to said other side of the piston said cylinder having aperture means on the other side of said piston to allow outflow of the liquid when the control unit releases the piston, and said control unit having an outlet for the liquid and comprising a piston for selectively blocking said outlet and linkage means acting on said piston to hold the same in a position in which the outlet is blocked.

2. Apparatus as claimed in claim 1 wherein said linkage means is a releasable toggle linkage, said control unit comprising a resistance means coupled to said toggle linkage to cushion impact on the piston in the control unit when the linkage means is released, said toggle linkage modulating the force on the resistance means.

3. Apparatus as claimed in claim I wherein said thrust unit comprises a thrust rod coupled to said piston for movement therewith, a thrust block adapted for bearing against the muzzle of the ordnance piece and clutch means between the thrust block and thrust rod.

4. Apparatus as claimed in claim 3 wherein said thrust block is rotatable and said clutch means comprises claw coupling members on said block and rod, said coupling members being in axial alignment to transmit axial force in initial position of the thrust unit and being out of alignment to decouple the rod and block after thrust has been applied to said muzzle.

5. Apparatus as claimed in claim 4 wherein said thrust unit comprises spring means between said block and rod for returning the same to their initial position after thrust has been applied to said muzzle.

* k n a 5 

1. Apparatus for the testing of ordnance pieces comprising a power unit adapted for generating thrust for application to an ordnance piece, and a thrust unit coupled to said power unit for transmitting thrust to said ordnance piece at the muzzle thereof, said power unit comprising a cylinder, a piston in said cylinder defining on one side thereof, a closed chamber with a gas therein, means acting on said piston on the other side thereof to compress the gas in said closed chamber and hold the same under pressure and to release the piston for rapid movement and means coupling the piston and thrust unit to transmit the rapid movement of the piston to the thrust unit and thence to the ordnance piece, a control unit regulating release of the piston, said means acting on the other side of the piston to compress the gas comprising means for the supply of a liquid under pressure to said other side of the piston , said cylinder having aperture means on the other side of said piston to allow outflow of the liquid when the control unit releases the piston, and said control unit having an outlet for the liquid and comprising a piston for selectively blocking said outlet and linkage means acting on said piston to hold the same in a position in which the outlet is blocked.
 2. Apparatus as claimed in claim 1 wherein said linkage means is a releasable toggle linkage, said control unit comprising a resistance means coupled to said toggle linkage to cushion impact on the piston in the control unit when the linkage means is released, said toggle linkage modulating the force on the resistance means.
 3. Apparatus as claimed in claim 1 wherein said thrust unit comprises a thrust rod coupled to said piston for movement therewith, a thrust block adapted for bearing against the muzzle of the ordnance piece and clutch meanS between the thrust block and thrust rod.
 4. Apparatus as claimed in claim 3 wherein said thrust block is rotatable and said clutch means comprises claw coupling members on said block and rod, said coupling members being in axial alignment to transmit axial force in initial position of the thrust unit and being out of alignment to decouple the rod and block after thrust has been applied to said muzzle.
 5. Apparatus as claimed in claim 4 wherein said thrust unit comprises spring means between said block and rod for returning the same to their initial position after thrust has been applied to said muzzle. 